Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add personamanagmentlayer/pcl --skill selenium-expertgit clone --depth 1 https://github.com/personamanagmentlayer/pclWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/personamanagmentlayer/pcl/selenium-expert)<a href="https://agentmods.dev/skills/personamanagmentlayer/pcl/selenium-expert"><img src="https://agentmods.dev/badge/skills/personamanagmentlayer/pcl/selenium-expert/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/personamanagmentlayer/pcl/selenium-expert"><img src="https://agentmods.dev/badge/skills/personamanagmentlayer/pcl/selenium-expert.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00072 | $0.01107 |
| Opus 5.5 | $0.00029 | $0.00443 |
| Sonnet 5.5 | $0.00014 | $0.00221 |
| Haiku 4.5 | $0.00007 | $0.00111 |
Grade A, and why
selenium-expert scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 169 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Selenium Expert
Core Concepts
Selenium Components
- WebDriver - Browser automation API
- Selenium Grid - Distributed test execution
- IDE - Record and playback tool
- Locator Strategies - Find elements (ID, CSS, XPath)
- Wait Mechanisms - Explicit, implicit, fluent waits
- Actions API - Complex user interactions
Browser Support
- Chrome/Chromium - ChromeDriver
- Firefox - GeckoDriver
- Safari - SafariDriver
- Edge - EdgeDriver
- IE - IEDriver (legacy)
- Remote - Selenium Grid execution
Advanced Features
- Page Object Model - Design pattern
- Test Frameworks - TestNG, JUnit, pytest
- Parallel Execution - Grid and ThreadLocal
- Screenshots - Visual verification
- JavaScript Execution - Execute custom scripts
- Mobile Testing - Appium integration
Best Practices
Locator Strategy
- Prefer ID over other locators
- Use CSS selectors over XPath
- Add data-testid attributes
- Avoid fragile locators
- Use relative locators (Selenium 4+)
- Document locator choices
Wait Strategy
- Use explicit waits over implicit
- Set appropriate timeouts
- Wait for specific conditions
- Avoid Thread.sleep()
- Handle stale elements
- Use fluent waits for complex conditions
Test Design
- Implement Page Object Model
- Keep tests independent
- Use proper test data management
- Implement proper cleanup
- Handle flaky tests
- Log and screenshot failures
Performance
- Reuse browser sessions when possible
- Use parallel execution
- Optimize wait times
- Close unused windows/tabs
- Clear cache between tests
- Monitor Grid performance
Anti-Patterns
Common Mistakes
- Using sleep instead of waits
- Hard-coded wait times
- Not handling stale elements
- Missing implicit wait configuration
- Too many XPath locators
- No error handling
Locator Issues
- Brittle XPath expressions
- Using absolute XPath
- Relying on index positions
- No fallback locators
- Missing data-testid attributes
- Coupling to UI changes
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 169 lines · 72 tokens per session scan A 381e062ad6fc
selenium-expert is a skill published in the GitHub repository personamanagmentlayer/pcl (43 stars, last pushed 11d ago), licensed Apache-2.0. It adds 72 tokens to every session and 1,107 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-05.
Other skills, from other repositories
proof-e2e
Build E2E test specs for critical user journeys — Playwright or Cypress, page objects, setup/teardown, CI config. Use when asked to "write E2E tests", "end-to-end testing", "browser tests", "UI tests", or "Playwright tests".
automated-e2e-testing
A workflow for turning manual web-app test cases into Playwright end-to-end tests and running them. End-to-end tests check a complete user flow through the website.
qa-testing
Run QA testing on a page, feature, or full site at one of three depth tiers (smoke, standard, full). Use this skill whenever the user asks to QA a page or site, run a smoke test after a deploy, verify a page before launch, or run a regression sweep. Triggers on QA, QA sweep, smoke test, regression test, post-deploy…
e2e-testing-patterns
Build reliable, fast E2E test suites with Playwright and Cypress. Critical user journey coverage, flaky test elimination, CI/CD integration.
playwright-test
Run end-to-end browser tests using the Playwright Test CLI. Create test configs, write spec files with expect assertions, execute tests with npx playwright test, and analyze results. Pre-installed with Chromium in the computer image — no setup needed. Use for E2E testing, regression testing, smoke tests, visual…
dogfood
Exploratory QA of web apps: find bugs, evidence, reports.